Electrical fuse-plug.



J. S. JOHNSTON.

ELEGTBIGAL FUSE PLUG.

APPLICATION FILED MAR. I5, 1909.

1,050,062. Patented m1111913.

ATTORNEYS UNITED sims PATENT OFFICE.

JAMES S. JOHNSTON, F UTICA, NEW YORK, SSIGNOR, BY DIRECT AND MESNE rAAS- SIGNMENTS, TO JOHNSTON MANUFACTURING COMPANY, OF UTICA, NEW YORK, A

CORPORATION 0F NEW YORK.

ELEGTRICAL FUSE-PLUG.

To all whom rit-may concern.'

Be it known that I, JAMES S. JOHNSTON, of Utica, in the county of Oneida and State of New York, have invented certain new and useful Improvements in Electrical Fuse-Plugs; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others Skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form part of this specification.

' The object of my present invention is to provide an electric safety fuse plug, which is simple in construction, eiiicient, can be readily renewed as to the fuse and restored to its working condition, and in some of the forms of construction shown is adapted to cut oif any tendency to arcing when the fuse blows out.` There is also an indicator for indicating the fact thatthe fuse has blown.

Figure 1 shows a longitudinal sectional View of a fuse plug embodying the features of my invention. Fig. 2 shows a cross sectional view taken on line 22 of Fig. 1, showing the device in its normal working condition.. Fig. 3 is a similar cross sectional view showing the device after the fuse has blown. Fig. 4 is a longitudinal sectional view of a modified form of construction. Fig. 5 is a cross sectional view taken onA line 5 5 of Fig. 4. Fig. 6 is another cross sectional view taken on line 6-6 of Fig. 4. Fig. 7 is another cross sectional view taken on line 7-7 of Fig. 4. Fig. 8 is a side elevation of one end of the tubular case employed in the construction as shown in Figs. 1 and 4.

Referring to the reference letters and figures in a more particular description, 15 indicates a tubular casing of insulating ma` terial and preferably transparent glass. Covering the ends of the casing are metallic caps 16 and 17 detachably secured to the casing preferably by being provided withl internal projections, as 18, engaging in bayonet catch recesses 19 in the walls of the casing adjacent to and running-out to the ends.

As to the form of construction shown in Fi 1, the caps are provided *with exteryna y projecting blades 16 and 17a adapted Specification of Letters Patent.

I Application filed March 15, 1909.

Patented J an. 7, 1913.

Serial No. 483,344.

to be inserted in spring clamps as on a switch board in the usual manner of fuse plugs of this character. The blades 16a and 17a are carried t-o the interior in internal extensions 16b and 17h. The casing is adapted to receive a fuse holder of insulating material made, as shown in Fig. 1, preferably in two parts, 2O. and 20, swiveled or pivoted for relative rotation on an axial pivot or pintle 21. 1n general form the fuse holder is a cylinder flattened along one side to provide a passage for the fuse strip 22. Each end of the fuse holder is provided with a slotted recess adapted to receive the internal extensions 16b and 17 b of the 'conduc tor blades. The ends of the fuse strip 22 are folded around the ends of the fuse holder and also inserted in the recesses which receive the internal extensions 1Gb and 17h. lin fact, the latter are inserted last into these sockets or recesses, and serve to Wedge or bind the ends of the fuse strip within the socket, 'as well as make electrical contact at this point. Substantially in the middle of the fuse holder, there is provided a recess extending out to that side which is attened off to receive the fuse strip, in which is located a cut-off gate or late 23 of a segmental form on its outer ey ge, substantially conforming to the circle of the inner face of the casing, and provided with a stem 23a entering a suitable'socket or extension of the recess and backed by a spring 24 tensione'd to force the gate or cut-off outward'ly from the recess. The gate 23 is preferably provided with an indicator pin 25, which is removably secured in the edge of the gate or plate 23 by being screwthreaded therein, and the projecting end of which passes into or through a hole in the casing arranged at a suitable point. The fuse strip 22 will be provided with a perforation at the point where the indicator pin 25 is located, and the arrangement will preferably be such that the cross sectional area of the fuse strip will be thev smallest at this point. y

rIhe parts may be assembled by applying the fuse strip to the fuse holder when removed from the casing, the part 23 being forced by-hand into its recess and the ten; sion on the fuse strip as it is held taut along the side of the fuse holder being sufiicient to hold it retired in its recess. The indicator rotated in engaging them in the bayonet catch recess and locking them on the ends of the case. The arrangement of all parts will be such that at the final limits of their movement, the iat sides on the two parts yof the fuse holder will register and the fuse be held taut in a true plane. When the parts are thus assembled, the indicator pin 25 will be inserted through the opening in the casing and secured in the gate or cut-off plate 23. The length of this pin 25 will preferably be such as to not project from the outer wall of the shell whenthe parts are all in normal working condition. The pin 25 may also serve as a guide for theplate 23.

It is obvious that the device when assembled is capable of carrying electrical current by means of the fuse strip 22 from one of the contact blades 16l to the other contact blade as 17 or vice versa. In case of excessive current the fuse strip burns or blows at its point of smallest area, which will be opposite the cut'foif plate 23. When this happens there is nothing to rest-rain the spring 24, andthe cut-olf plate 23- is forced outwardly completely closing the tubular opening through the casing at this point. The fuse holder may be largely cut out and recessed around its periphery, substantially as shown, whereby provision is made for the accumulation of some gases and products ofy combustion when the fuse blows without excessive internal pressure. When the cut-o plate or gate 23 is projected to close the tubular opening through the casing, any tendencyto are between the swiveled ends of the fuse strip is provided against or an are forming at-this point is cut off. It might be noted that the gate or plate 23 is preferably of insulating material.

-At the time the plate 23 is operated, the outer end of the indicator pin 25 is projected, whereby it may be readily determined by observation or feeling that the fuse has been blown and the device is no longer operative as an electric current conductor. The parts may then be readily taken apart and the remnants of the old fuse strip removed and a new one su plied, and 'the/parts re-assembled, when t e device is ready for use again in as good condition as new. When the casing 15 is of transparent material, as glass, the condition of the fuse strip can be readily observed. The casing, however, may be made Vcap in an extension or bit 34. The fuse holder shown in this form of construction consists of two parts, 35a and 35", which are relatively rotatable or swiveled together by being provided with a pintle as to part 35, which enters a socket in the part 35h, and are held extended longitudinally by a spring 35C. The fuse strip 36, which, in this case, is used doubled, is folded around one end of the fuse holder and inserted in the socket 33, while the other ends of the fuse strip are folded into a notch er recess in the other end of the fuse holder and wedged and held therein by the bit 34. The tension on the fuse strip is suiiicient to hold the spring 35 under compression. The fuse strip makes electrical contact with the socket 33 at one end of the fuse holder, andat the other end of the fuse holder makes electrical contact with the blade 34, which, as before stated, is wedgedin between the two ends of the fuse strip. It is obvious that this construction will carry electrical currentvfrom the 'contact blade 31a to the contact blade 32* cations of constructions than those herein described may be made without departing from the invention hereinafter intended to be claimed.

What I claim as new anddesire to secure by Letters Patent is:

l. The combination in an electric safety fuse of a tubular casing of insulating material, caps closingthe ends of the casing and having internal means for'making electrical connection, a fuse 'holder extending between said means, a fuse held by the holder in electrical lcontact with said means, and means operating in connection with the fuse holder to completely close the tubular opening through' the casing when the fuse prevent excessive interna-l pressure in said blows, substantially as set forth. casing, and a fuse disposed in said fuse 2. In a fuse of the character described, holder, substantially as described. the combination of a tubular casing, end In witness whereof, I have affixed my sig- 5 members adapted to frictionally engage said nature, in presence of two witnesses, this 15 casing, whereby the contents of said casing 3rd day of February, 1909.

may be quickly. removed, a fuse holder dis- JAMES S. JOHNSTON. posed in said casing, said fuse holder being Witnesses: cut out around its periphery, whereby to EMMA S. Hman,

16 provide for the accumulation of gases to SARAH E. CLARK. 

